Cooling system for a battery system and a method for cooling the battery system

ABSTRACT

A cooling system for a battery system and a method for cooling the battery system are provided. The cooling system includes a housing having first and second enclosed portions, and a first evaporator and a first evaporator fan disposed in the first enclosed portion that recirculates air in a first closed flow path loop within the first enclosed portion. The first evaporator extracts heat energy from the air in the first closed flow path loop to reduce a temperature level of a first battery module in the first enclosed portion. The cooling system further includes a condenser disposed in the second enclosed portion and fluidly coupled to the first evaporator, which receives heat energy in a refrigerant from the first evaporator and dissipates the heat energy. The cooling system further includes a compressor disposed in the second enclosed portion that recirculates the refrigerant through the first evaporator and the condenser.

TECHNICAL FIELD

This application relates to a cooling system for a battery system and amethod for cooling the battery system.

BACKGROUND OF THE INVENTION

In a typical air-cooled battery pack, ambient air from ambientatmosphere is directed across battery cells in the battery pack and issubsequently exhausted from the battery pack. However, the typicalair-cooled battery pack has a major challenge in maintaining atemperature of the battery pack within a desired temperature range.

In particular, a maximum operating temperature of the battery cells canoften be less than a temperature of ambient air utilized to cool thebatteries. In this situation, it is impossible to maintain the batterycells within a desired temperature range in an air-cooled battery pack.

Accordingly, the inventors herein have recognized a need for an improvedbattery cell assembly that minimizes and/or eliminates theabove-mentioned deficiency.

SUMMARY OF THE INVENTION

A cooling system for a battery system in accordance with an exemplaryembodiment is provided. The cooling system includes a housing having afirst enclosed portion and a second enclosed portion. The first enclosedportion is configured to receive a first battery module therein. Thecooling system further includes a first evaporator disposed in the firstenclosed portion. The cooling system further includes a first evaporatorfan disposed proximate to the first evaporator in the first enclosedportion configured to recirculate air in a first closed flow path loopwithin the first enclosed portion. The first evaporator is configured toextract heat energy from the air in the first closed flow path loop toreduce a temperature level of the first battery module. The coolingsystem further includes a condenser disposed in the second enclosedportion and fluidly coupled to the first evaporator. The condenser isconfigured to receive heat energy in a refrigerant from the firstevaporator and to dissipate the heat energy. The cooling system furtherincludes a compressor disposed in the second enclosed portion thatrecirculates the refrigerant through the first evaporator and thecondenser.

A method for cooling a battery system utilizing a cooling system inaccordance with another exemplary embodiment is provided. The coolingsystem has a housing, a first evaporator, a first evaporator fan, and acondenser. The housing has a first enclosed portion and a secondenclosed portion. The first enclosed portion is configured to receive afirst battery module therein. The method includes recirculating air in afirst closed flow path loop within the first enclosed portion utilizingthe first evaporator fan. The first evaporator is configured to extractheat energy from the air in the first closed flow path loop to reduce atemperature level of the first battery module in the first enclosedportion of the housing. The method further includes receiving heatenergy in a refrigerant from the first evaporator in a condenserdisposed in the second enclosed portion of the housing and dissipatingthe heat energy utilizing the condenser. The method further includesrecirculating the refrigerant through the first evaporator and thecondenser utilizing a compressor disposed in the second enclosedportion.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic of a power generation system having a batterysystem and a cooling system in accordance with an exemplary embodiment;

FIG. 2 is a schematic of a portion of a housing, battery modules, andthe cooling system utilized in the power generation system of FIG. 1;

FIG. 3 is a schematic of a top view of the housing, battery modules, andthe cooling system utilized in the power generation system of FIG. 1;

FIG. 4 is a cross-sectional schematic of the power generation system ofFIG. 1;

FIG. 5 is a block diagram of components of the cooling system utilizedin the power generation system of FIG. 1;

FIG. 6 is a schematic of a portion of the housing and the cooling systemutilized in the power generation system of FIG. 1;

FIG. 7 is another schematic of a portion of the housing and the coolingsystem utilized in the power generation system of FIG. 1;

FIG. 8 is another schematic of a portion of the housing, batterymodules, and the cooling system utilized in the power generation systemof FIG. 1;

FIG. 9 is another schematic of a portion of a housing, battery modules,and the cooling system utilized in the power generation system of FIG.1;

FIG. 10 is an enlarged schematic of a portion of one battery moduleshown in FIG. 9;

FIG. 11 is another schematic of a portion of the housing, batterymodules, and the cooling system utilized in the power generation systemof FIG. 1;

FIGS. 12-19 are flowcharts of a method for cooling a battery system inaccordance with another exemplary embodiment; and

FIG. 20 is a schematic of a portion of a housing, battery modules, andthe cooling system utilized in another power generation system inaccordance with another exemplary embodiment.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Referring to FIGS. 1-3, a power generation system 10 for outputtingelectrical power in accordance with an exemplary embodiment isillustrated. The power generation system 10 includes a battery system 20and a cooling system 22.

The battery system 20 is provided to output electrical power. Thebattery system 20 includes the battery modules 24, 26. Each of thebattery modules 24, 26 has a similar structure and includes a pluralityof battery cell assemblies that can be electrically connected in seriesto one another or in parallel to one another. For purposes of brevity,only a portion of the battery cell assemblies in the battery module 24will be described in detail. For example, referring to FIGS. 8-10, thebattery module 24 includes battery cell assemblies 28, 29, 30, 31, 32,33, 34, 36, 38, 40 and 42 and flow channel manifolds 60, 62, 64, 66, 68,70, 72, 74, 76 and 78. Each of the battery cell assemblies has a batterycell therein that generates an operational voltage between a pair ofelectrodes extending therefrom. In one exemplary embodiment, eachbattery cell is a lithium-ion battery cell. In alternative embodiments,the battery cells could be nickel-cadmium battery cells or nickel metalhydride battery cells for example. Of course, other types of batterycells known to those skilled in the art could be utilized.

The flow channel manifolds are provided to allow air to flow through airchannels defined in each flow channel manifold. The air that flowsthrough a flow channel manifold that is disposed between adjacentbattery cell assemblies, extracts heat energy from the adjacent batterycell assemblies.

For example, referring to FIG. 4, a brief explanation of the flowchannel manifold 60 will be provided. It should be noted that thestructure of flow channel manifolds 62, 64, 66, 68, 70, 72, 74, 76 and78 have the same structure as flow channel manifold 60. As shown, theflow channel manifold 60 has an upper rail member 82, a lower railmember 84, and a plurality of vertical members 86. The upper rail member82 and the lower rail member 84 are disposed substantially parallel toeach another. The plurality of vertical members 86 are connected betweenthe upper rail member 82 and the lower rail member 84 and are disposedsubstantially parallel to each other. The plurality of vertical members86 are spaced apart from each other and define a plurality of air flowchannels therein. For example, some of the vertical members 86 defineair flow channels 100, 102, 104 (on a right side of FIG. 4) in the flowchannel manifold 60. Further, some of the vertical members 86 define airflow channels 106, 108, 110 (on a left side of FIG. 4) in the flowchannel manifold 60.

Referring to FIG. 10, the flow channel manifold 60 is disposed betweenthe battery cell assemblies 28, 29, and the flow channel manifold 62 isdisposed between the battery cell assemblies 29, 30. Further, the flowchannel manifold 64 is disposed between the battery cell assemblies 30,31, and the flow channel manifold 66 is disposed between the batterycell assemblies 31, 32. Further, the flow channel manifold 68 isdisposed between the battery cell assemblies 32, 33 and the flow channelmanifold 70 is disposed between the battery cell assemblies 33, 34.Further, the flow channel manifold 72 is disposed between the batterycell assemblies 34, 36, and the flow channel manifold 74 is disposedbetween the battery cell assemblies 36, 38. Further, the flow channelmanifold 76 is disposed between the battery cell assemblies 38, 40, andthe flow channel manifold 78 is disposed between the battery cellassemblies 40, 42.

Referring to FIGS. 2, 3 and 5-8, the cooling system 22 is provided tomaintain a battery system 20 within a desired temperature range, and inparticular below a threshold temperature level in accordance with anexemplary embodiment is provided. The cooling system 22 includes ahousing 130, evaporator fans 132, 134, evaporators 136, 138, flowbalancing baffles 140, 142, a support member 144, conduit portions 146,148, 150, flow balancing trays 160, 162, inner side walls 170, 172, 174,a dividing wall 176, a condenser 190, a condenser fan 192, thecompressor 194, conduit portions 196, 198, 200, temperature sensors 210,212, and a microprocessor 220. In one exemplary embodiment, the coolingsystem 22 can maintain the battery modules 24, 26 within a desiredtemperature range of 15°-35° Celsius. Of course, other temperatureranges could also be utilized. In another exemplary embodiment, thecooling system 22 can maintain the battery modules 24, 26 at atemperature level less than a threshold temperature level of 40°Celsius. Of course, another threshold temperature level could beutilized.

Referring to FIG. 1, the housing 130 is provided to enclose the batterysystem 20 and the cooling system 22 therein. The housing 130 includes abase member 230, a top cover 232 configured to be coupled to the basemember 230, and standoff members 234, 236 that are disposed on thebottom surface of the base member 230. In one exemplary embodiment, thehousing 130 is constructed from plastic. However, in alternativeembodiments other materials known to those skilled in the art could beutilized to construct the housing 130.

Referring to FIGS. 1, 6 and 8, the evaporators 136, 138 are provided toextract heat energy from the battery modules 24, 26, respectively. Theevaporators 136, 138 are disposed on the base member 230 of the housing130. Further, the evaporators 136, 138 are disposed in an enclosedportion or space 180 within the housing 130. The evaporator 136 isconfigured to extract heat energy from air in a first closed flow pathloop (described below) into a refrigerant flowing through the evaporator136 to reduce a temperature level of the battery module 24. Similarly,the evaporator 138 is configured to extract heat energy from air in asecond closed flow path loop (described below) into a refrigerantflowing through the evaporator 138 to reduce a temperature level of thebattery module 26. Exemplary refrigerants include R-11, R-12, R-22,R-134A, R-407C and R-410A for example. Of course, other types ofrefrigerants known to those skilled in the art could be utilized.

Referring to FIGS. 3, 4 and 6, a refrigerant flow path in the coolingsystem 22 will now be explained. As shown, the evaporator 136 is fluidlycoupled to the compressor 194 via the conduit portions 200, 146.Further, the evaporator 136 is fluidly coupled to the evaporator 138 viathe conduit portion 148. Further, the evaporator 138 is fluidly coupledto the condenser 190 via the conduit portions 150, 196. Further, thecondenser 190 is fluidly coupled to the compressor 194 via the conduitportion 198. During operation, the compressor 194 pumps the refrigerantthrough a closed loop including the conduit portions 200, 146, theevaporator 136, the conduit portion 148, the evaporator 138, the conduitportions 150, 196, the condenser 190, the conduit portion 198 and backto the compressor 194.

Referring to FIGS. 4 and 6, the evaporator fan 132 is disposed on thebase member 230 of the housing 130. The evaporator fan 132 is configuredto recirculate air in a closed flow path loop 240 within the firstenclosed portion 180 of the housing 130. The closed flow path loop 240includes a flow path through the evaporator fan 132, and past theevaporator 136 and then through air flow channels in the battery module24 and then back through the evaporator fan 132.

The evaporator fan 134 is disposed on the base member 230 of the housing130. The evaporator fan 134 is configured to recirculate air in a closedflow path loop 242 within the enclosed portion 182 of the housing 130.The closed flow path loop 242 includes a flow path through theevaporator fan 134, and past the evaporator 136 and then through airflow channels in the battery module 26 and then back through theevaporator fan 134.

The flow balancing baffle 140 is disposed proximate to the evaporatorfan 132 on the base member 230 of the housing 130. The flow balancingbaffle 140 is configured to allow a substantially equal amount of airflow through each aperture in the baffle 140 such than air flow isevenly distributed across a surface of the evaporator 136. In oneexemplary embodiment the flow balancing baffle 140 is substantiallyu-shaped with a plurality of apertures extending therethrough and isconstructed from plastic.

The flow balancing baffle 142 is disposed proximate to the evaporatorfan 134 on the base member 230 of the housing 130. The flow balancingbaffle 142 is configured to allow a substantially equal amount of airflow through each aperture in the baffle 142 such than air flow isevenly distributed across a surface of the evaporator 138. In oneexemplary embodiment, the flow balancing baffle 142 is substantiallyu-shaped with a plurality of apertures extending therethrough and isconstructed from plastic.

The support member 144 is disposed on the base member 230 of the housing130 between the evaporators 136, 138. In one exemplary embodiment, thesupport member 144 is substantially u-shaped and is constructed fromplastic.

Referring to FIG. 6, the conduit portion 146 is fluidly coupled to afirst end of the evaporator 136. The conduit portion 148 is fluidlycoupled between a second end of the evaporator 136 and a first end ofthe evaporator 138. Further, the conduit 150 is fluidly coupled to asecond end of the evaporator 138. Thus, refrigerant can flow through theconduit portion 160, the evaporator 136, the conduit portion 148, theevaporator 138, and the conduit 150.

Referring to FIG. 7, the flow balancing tray 160 is disposed on the flowbalancing baffles 140, 142 and the support member 144 in the enclosedportion 180 of the housing 130. The flow balancing tray 160 isconfigured to allow a substantially equal amount of air flow througheach aperture in the tray 160 such that air flow is evenly distributedacross lower surfaces of the battery modules 24, 26. Further, the flowbalancing tray 160 is configured to hold the battery modules 24, 26thereon. In one exemplary embodiment, the flow balancing tray 160 has aplurality of apertures extending therethrough and is constructed fromplastic.

Referring to FIG. 11, the flow balancing tray 162 is disposed on a topsurface of the battery modules 24, 26 in the housing 130. The flowbalancing tray 162 is configured to allow a substantially equal amountof air flow through each aperture in the tray 162 such than air flow isevenly distributed from the battery modules 24, 26 through the flowbalancing tray 162. In one exemplary embodiment, the flow balancing tray162 has a plurality of apertures extending therethrough and isconstructed from plastic.

Referring to FIGS. 1 and 11, the inner side walls 170, 172, 174 and thedividing wall 176 are disposed proximate to side walls of the batterymodules 24, 26. The dividing wall 176 has a sealing gasket 177 disposedon an outer periphery of the dividing wall 176 to form an airtight sealwith the base member 230 and the top cover 232 that contact the outerperiphery of the dividing wall 176. Further, the base member 230, thetop cover 232 and the dividing wall 176 define an enclosed portion 180having the battery modules 24, 26 disposed therein. It should be notedthat the enclosed portion 180 is an airtight enclosed portion. Further,the base member 230, the top cover 232 and the dividing wall 176 definean enclosed portion 184. In one exemplary embodiment, the enclosedportion 184 fluidly communicates with ambient air external to thehousing 130. In one exemplary embodiment, the inner side walls 170, 172,174 and the dividing wall 176 are constructed from plastic.

Referring to FIGS. 3 and 6, the condenser 190 is disposed in theenclosed portion 182 of the housing 130 and is fluidly coupled to theevaporators 136, 138 and the compressor 194. As shown, the condenser 190is fluidly coupled to the evaporator 138 via the conduit portions 150,196. Further, the condenser 190 is fluidly coupled to the compressor 194via the conduit portion 198. The condenser 190 is configured to receiveheat energy in a refrigerant from the evaporators 136, 138 and todissipate the heat energy in the received refrigerant such that the heatenergy is removed from the refrigerant for cooling the battery modules24, 26.

Referring to FIGS. 3 and 5, the condenser fan 192 is configured to urgeair past the condenser 190 to induce the condenser 190 to dissipate heatenergy in response to a control signal from the microprocessor 220. Asshown, the condenser fan 192 is disposed proximate to the condenser 190in the enclosed region 182.

Referring to FIGS. 3, 5 and 6, the compressor 194 is configured to pumpand recirculate refrigerant through the evaporators 136, 138 in responseto a control signal from the microprocessor 220. In particular, thecompressor 194 pumps the refrigerant through a closed loop including theconduit portions 200, 146, the evaporator 136, the conduit portion 148,the evaporator 138, the conduit portions 150, 190, the condenser 190,and the conduit portion 198 back to the compressor 194. As shown, thecompressor 194 is disposed in the enclosed region 182.

Referring to FIGS. 3 and 5, the temperature sensor 210 is electricallycoupled to the microprocessor 220 and is disposed proximate to thebattery module 24. The temperature sensor 210 is configured to generatea signal indicative of a temperature of the battery module 24 that isreceived by the microprocessor 220.

The temperature sensor 212 is electrically coupled to the microprocessor220 and is disposed proximate to the battery module 26. The temperaturesensor 212 is configured to generate a signal indicative of atemperature of the battery module 26 that is received by themicroprocessor 220.

The microprocessor 212 is configured to control operation of the coolingsystem 22. As shown, the microprocessor 212 is electrically coupled tothe evaporator fans 132, 134, the condenser fan 192, the compressor 194,and the temperature sensors 210, 212. During operation, themicroprocessor 212 receive signals from the temperature sensors 210, 212indicative of temperatures of the battery modules 24, 26, respectively.Based on the received signals from the temperature sensors 210, 212, themicroprocessor 212 generates control signals for controlling operationof the evaporator fans 132, 134, the condenser fan 192, and thecompressor 194, as will be explained in greater detail below.

Referring to FIGS. 12-19, a flowchart of a method for cooling thebattery system 20 will now be explained.

At step 260, the microprocessor 220 initializes the following flags:flag1 equals “false”; flag2 equals “false”; flag3 equals “false”; andflag4 equals “false.” After step 260, the method advances to step 262.

At step 262, the temperature sensor 210 generates a first signalindicative of a temperature of the battery module 24 disposed in theenclosed portion 180 of the housing 130 that is received by themicroprocessor 220. After step 262, the method advances to step 264.

At step 264, the temperature sensor 212 generates a second signalindicative of a temperature of the battery module 26 disposed in theenclosed portion 180 of the housing 130 that is received by themicroprocessor 220. After step 264, the method advances to step 266.

At step 266, the microprocessor 220 makes a determination as to whetherthe first signal from the temperature sensor 210 indicates that atemperature level of the battery module 24 is greater than a thresholdtemperature level. If the value of step 266 equals “yes”, the methodadvances to step 268. Otherwise, the method advances to step 286.

At step 268, the microprocessor 220 sets flag1 equal to “true.” Afterstep 268, the method advances to step 270.

At step 270, the microprocessor 220 generates a signal to turn on thecompressor 194 to recirculate refrigerant through evaporators 132, 134disposed proximate to battery module 24, 26, respectively in theenclosed portion 180 of the housing 130, and through the condenser 190disposed in the enclosed portion 182 of the housing 130. After step 270,the method advances to step 280.

At step 280, the microprocessor 220 generates a signal to turn on theevaporator fan 132 to recirculate air in a first closed flow path loop240 (shown in FIG. 4) within the enclosed portion 180. The first closedflow path loop 240 includes a flow path through the evaporator fan 132and past the evaporator 136 and then through air flow channels in thebattery module 24 and then back through the evaporator fan 132. Afterstep 280, the method advances to step 282.

At step 282, the evaporator 136 extracts heat energy from the air in thefirst closed flow path loop 240 to the refrigerant flowing through theevaporator 136 to reduce a temperature of the battery module 24 in theenclosed portion 180. After step 282, the method advances to step 284.

At step 284, the microprocessor 220 generates a signal to turn on thecondenser fan 192 to urge air past the condenser 190 in the enclosedportion 182 that further induces the condenser 190 to dissipate heatenergy from the refrigerant flowing from the evaporator 136. After step284, the method advances to step 304.

Referring again to step 266, when the value of step 266 equals “no”, themethod advances to step 286. At step 286, the microprocessor 220 setsflag1 equal to “false.” After step 286, the method advances to step 288.

At step 288, the microprocessor 220 makes a determination as to whetherthe flag4 equals “false.” If the value of step 288 equals “yes”, themethod advances to step 290. Otherwise, the method advances to step 292.

At step 290, the microprocessor 220 removes a signal from the evaporatorfan 132 to turn off the evaporator fan 132. After step 290, the methodadvances to step 292.

At step 292, the microprocessor 220 makes a determination as to whetherthe flag2 equals “false”; flag3 equals “false” and flag4 equals “false.”If the value of step 292 equals “yes”, the method advances to step 300.Otherwise, the method advances to step 304.

At step 300, the microprocessor 220 removes a signal from the compressor194 to turn off the compressor 194. After step 300, the method advancesto step 302.

At step 302, the microprocessor 220 removes a signal from the condenserfan 192 to turn off the condenser fan 192. After step 302, the methodadvances to step 304.

At step 304, the microprocessor 220 makes a determination as to whetherthe second signal from temperature sensor 212 indicates that atemperature level of the battery module 26 is greater than the thresholdtemperature level. If the value of step 304 equals “yes”, the methodadvances to step 306. Otherwise, the method advances to step 316.

At step 306, the microprocessor 220 sets flag2 equal to “true.” Afterstep 306, the method advances to step 308.

At step 308, the microprocessor 220 generates a signal to turn on thecompressor 194 to recirculate refrigerant through the evaporator 136,the evaporator 138, and the condenser 190. After step 308, the methodadvances to step 310.

At step 310, the microprocessor 220 generates a signal to turn on theevaporator fan 134 to recirculate air in a second closed flow path loop242 (shown in FIG. 4) within the enclosed portion 180. The second closedflow path loop 242 includes a flow path through the evaporator fan 134and past the evaporator 138 and then through air flow channels in thebattery module 26 and then back through the evaporator fan 134. Afterstep 310, the method advances to step 312.

At step 312, the evaporator 138 extracts heat energy from the air in thesecond closed flow path loop 242 to the refrigerant flowing through theevaporator 138 to reduce a temperature of the battery module 26 in theenclosed portion 180. After step 312, the method advances to step 314.

At step 314, the microprocessor 220 generates a signal to turn on thecondenser fan 192 to urge air past the condenser 190 in the enclosedportion 182 that further induces the condenser 190 to dissipate heatenergy from the refrigerant flowing from the evaporator 138. After step314, the method advances to step 330.

Referring again to step 304, if the value of step 304 equals “no”, themethod advances to step 316. At step 316, the microprocessor 220 setsflag2 equal to “false.” After step 316, the method advances to step 318.

At step 318, the microprocessor 220 makes a determination as to whetherthe flag3 equals “false.” If the value of step 318 equals “yes”, themethod advances to step 320. Otherwise, the method advances to step 322.

At step 320, the microprocessor 220 removes a signal from the evaporatorfan 134 to turn off the evaporator fan 134. After step 320, the methodadvances to step 322.

At step 322, the microprocessor 220 makes a determination as to whetherthe flag1 equals “false”; flag3 equals “false”; and flag4 equals“false.” If the value of step 322 equals “yes”, the method advances tostep 324. Otherwise, the method advances to step 330.

At step 324, the microprocessor 220 removes a signal from the compressor194 to turn off the compressor 194. After step 324, the method advancesto step 326.

At step 326, the microprocessor 220 removes a signal from the condenserfan 192 to turn off the condenser fan 192. After step 326, the methodadvances to step 330.

At step 330, the microprocessor 220 calculates a first temperaturedifference value utilizing the following equation: first temperaturedifference value=second signal−first signal. After step 330, the methodadvances to step 332.

At step 332, the microprocessor 220 makes a determination as to whetherthe first temperature difference value is greater than a thresholddifference value. If the value of step 332 equals “yes”, the methodadvances to step 334. Otherwise, the method advances to step 340.

At step 334, the microprocessor 220 sets flag3 equal to “true.” Afterstep 334, the method advances to step 335.

At step 335, the microprocessor 220 generates a signal to turn on thecompressor 194 to recirculate refrigerant through the evaporator 136,the evaporator 138, and the condenser 190. After step 335, the methodadvances to step 336.

At step 336, the microprocessor 220 generates a signal to turn on theevaporator fan 134 to recirculate air in the second closed flow pathloop 242 within the enclosed portion 180. After step 336, the methodadvances to step 337.

At step 337, the evaporator 138 extracts heat energy from the air in thesecond closed flow path loop 242 to the refrigerant flowing through theevaporator 138 to reduce a temperature of the battery module 26 in theenclosed portion 180. After step 337, the method advances to step 338.

At step 338, the microprocessor 220 generates a signal to turn on thecondenser fan 192 to urge air past the condenser 190 in the enclosedportion 182 of the housing 130 that further induces the condenser 190 todissipate heat energy from the refrigerant flowing from the evaporator138. After step 338, the method advances to step 360.

Referring again to step 332, when the value of step 332 equals “no”, themethod advances to step 340. At step 340, the microprocessor 220 setsflag3 equal to “false.” After step 340, the method advances to step 342.

At step 342, the microprocessor 220 makes a determination as to whetherthe flag2 equals “false.” If the value of step 342 equals “yes”, themethod advances to step 344. Otherwise, the method advances to step 346.

At step 344, the microprocessor 220 removes a signal from the evaporatorfan 134 to turn off the evaporator fan 134. After step 344, the methodadvances to step 346.

At step 346, the microprocessor makes a determination as to whether theflag1 equals “false”; flag2 equals “false”; and flag4 equals “false.” Ifthe value of step 346 equals “yes”, the method advances to step 348.Otherwise, the method advances to step 360.

At step 348, the microprocessor 220 removes a signal from the compressor194 to turn off the compressor 194. After step 348, the method advancesto step 350.

At step 350, the microprocessor 220 removes a signal from the condenserfan 192 to turn off the condenser fan 192. After step 350, the methodadvances to step 360.

At step 360, the microprocessor 220 calculates a second temperaturedifference value utilizing the following equation: second temperaturedifference value=first signal−second signal. After step 360, the methodadvances to step 362.

At step 362, the microprocessor makes a determination as to whether thesecond temperature difference value is greater than a thresholddifference value. If the value of step 362 equals “yes”, the methodadvances to step 364. Otherwise, the method advances to step 380.

At step 364, the microprocessor 220 sets flag4 equal to “true.” Afterstep 364, the method advances to step 366.

At step 366, the microprocessor 220 generates a signal to turn on thecompressor 194 to recirculate refrigerant through the evaporator 136,the evaporator 138, and the condenser 190. After step 366, the methodadvances to step 368.

At step 368, the microprocessor 220 generates a signal to turn on theevaporator fan 132 to recirculate air in the first closed flow path loop240 within the enclosed portion 180. After step 368, the method advancesto step 370.

At step 370, the evaporator 136 extracts heat energy from the air in thefirst closed flow path loop 240 to the refrigerant flowing through theevaporator 136 to reduce a temperature of the battery module 24 in theenclosed portion 180. After step 370, the method advances to step 372.

At step 372, the microprocessor 220 generates a signal to turn on thecondenser fan 192 to urge air past the condenser 190 in the enclosedportion 182 of the housing 130 that further induces the condenser 190 todissipate heat energy from the refrigerant flowing from the evaporator136. After step 372, the method returns to step 262.

Referring again to step 362, if the value of step 362 equals “no”, themethod advances to step 380. At step 380, the microprocessor 220 setsflag4 equal to “false.” After step 380, the method advances to step 382.

At step 382, the microprocessor 220 makes a determination as to whetherflag1 equals “false.” After step 382, the method advances to step 384.

At step 384, the microprocessor 220 removes a signal from the evaporatorfan 132 to turn off the evaporator fan 132. After step 384, the methodadvances to step 386.

At step 386, the microprocessor 220 makes a determination as to whetherflag1 equals “false”; and flag2 equals “false”; and flag3 equals“false.” If the value of step 386 equals “yes”, the method advances tostep 388. Otherwise, the method returns to step 262.

At step 388, the microprocessor 220 removes a signal from the compressor194 to turn off the compressor 194. After step 388, the method advancesto step 390.

At step 390, the microprocessor 220 removes a signal from the condenserfan 192 to turn off the condenser fan 192. After step 390, the methodreturns to step 262.

Referring to FIG. 20, a power generation system 418 for outputtingelectrical power in accordance with another exemplary embodiment isillustrated. The power generation system 418 includes a battery system420 and a cooling system 422. The battery system 420 has a substantiallysimilar configuration as the battery system 20. The cooling system 422has a cooling coil 424 and a condenser 490, and further includes theother components of the cooling system 22 described above except for thecondenser fan 192 and the condenser 190. The cooling coil 424 isutilized to cool the refrigerant and replaces the condenser fan 192utilized in the system 10. The condenser 490 replaces the condenser 190utilized in the cooling system 22. In operation, the cooling coil 424receives a liquid from an external liquid source which cools therefrigerant flowing therethrough. It should be noted that the operationof the cooling system 422 is similar to the operation of the coolingsystem 22 described above, except that the cooling coil 424 is utilizedinstead of a condenser fan to cool the refrigerant.

The cooling system for a battery system and the method for cooling thebattery system provide a substantial advantage over other coolingsystems and methods. In particular, the cooling system and methodprovide a technical effect of recirculating air in a closed flow pathloop within a housing of the cooling system to reduce a temperaturelevel of the battery modules in the battery system. The closed flow pathloop is within an airtight enclosed portion of the housing that allowsthe system and the method to utilize less power and have a smaller sizethan other systems and methods.

While the invention has been described with reference to exemplaryembodiments, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted forelements thereof without departing from the scope of the invention. Inaddition, many modifications may be made to adapt a particular situationor material to the teachings of the invention without departing from theessential scope thereof. Therefore, it is intended that the inventionnot be limited to the particular embodiment disclosed for carrying thisinvention, but that the invention will include all embodiments fallingwithin the scope of the appended claims. Moreover, the use of the terms,first, second, etc. are used to distinguish one element from another.Further, the use of the terms a, an, etc. do not denote a limitation ofquantity, but rather denote the presence of at least one of thereferenced items.

1. A cooling system for a battery system, comprising: a housing having afirst enclosed portion and a second enclosed portion, the first enclosedportion configured to receive a first battery module therein; a firstevaporator disposed in the first enclosed portion; a first evaporatorfan disposed proximate to the first evaporator in the first enclosedportion configured to recirculate air in a first closed flow path loopwithin the first enclosed portion, the first evaporator configured toextract heat energy from the air in the first closed flow path loop toreduce a temperature level of the first battery module; a condenserdisposed in the second enclosed portion and fluidly coupled to the firstevaporator, the condenser configured to receive heat energy in arefrigerant from the first evaporator and to dissipate the heat energy;and a compressor disposed in the second enclosed portion thatrecirculates the refrigerant through the first evaporator and thecondenser.
 2. The cooling system of claim 1, wherein the first closedflow path loop comprises a flow path through the first evaporator fanand past the first evaporator and then through air flow channels in thefirst battery module and then back through the first evaporator fan. 3.The cooling system of claim 1, further comprising a first temperaturesensor generating a first signal indicative of a temperature level ofthe first battery module.
 4. The cooling system of claim 3, furthercomprising: a condenser fan disposed in the second enclosed portion; amicroprocessor operably coupled to the first temperature sensor thatreceives the first signal, the microprocessor configured to generate asecond signal to induce the compressor to recirculate the refrigerantthrough the first evaporator and the condenser to cool the first batterymodule when the first signal indicates the temperature level of thefirst battery module is greater than a threshold temperature level; themicroprocessor further configured to generate a third signal to inducethe first evaporator fan to recirculate air in the first closed flowpath loop within the first enclosed portion when the first signalindicates the temperature level of the first battery module is greaterthan the threshold temperature level; and the microprocessor furtherconfigured to generate a fourth signal to induce the condenser fan tourge air past the condenser to induce the condenser to dissipate heatenergy when the first signal indicates the temperature level of thefirst battery module is greater than the threshold temperature level. 5.The cooling system of claim 1, further comprising: a second evaporatordisposed in the first enclosed portion, the second evaporator fluidlycoupled to the condenser; a second evaporator fan disposed proximate tothe second evaporator in the first enclosed portion, the secondevaporator fan configured to recirculate air in a second closed flowpath loop within the first enclosed portion, the second evaporatorconfigured to extract heat energy from the air in the second closed flowpath loop to reduce a temperature level of a second battery moduledisposed in the first enclosed portion; the condenser further fluidlycoupled to the second evaporator, the condenser further configured toreceive heat energy in refrigerant from the first and second evaporatorsand to dissipate the heat energy; and the compressor further configuredto recirculate the refrigerant through the first and second evaporatorsand the condenser.
 6. The cooling system of claim 5, wherein the secondclosed flow path loop comprises a flow path through the secondevaporator fan and past the second evaporator and then through air flowchannels in the second battery module and then back through the secondevaporator fan.
 7. The cooling system of claim 5, further comprising: afirst temperature sensor generating a first signal indicative of atemperature level of the first battery module, and a second temperaturesensor generating a second signal indicative of a temperature level ofthe second battery module.
 8. The cooling system of claim 7, furthercomprising: a condenser fan disposed in the second enclosed portion; amicroprocessor operably coupled to the first and second temperaturesensors that receives the first and second signals, respectively; themicroprocessor configured to determine a first temperature differencevalue by subtracting the first signal from the second signal; themicroprocessor further configured to generate a third signal to inducethe compressor to recirculate the refrigerant through the firstevaporator, the second evaporator, and the condenser to cool the secondbattery module when the first temperature difference value is greaterthan a threshold difference value; the microprocessor further configuredto generate a fourth signal to induce the second evaporator fan torecirculate air in the second closed flow path loop within the firstenclosed portion when the first temperature difference value is greaterthan the threshold difference value; and the microprocessor furtherconfigured to generate a fifth signal to induce the condenser fan tourge air past the condenser to induce the condenser to dissipate heatenergy in the refrigerant when the first temperature difference value isgreater than the threshold difference value.
 9. The cooling system ofclaim 7, further comprising: a condenser fan disposed in the secondenclosed portion; a microprocessor operably coupled to the first andsecond temperature sensors that receives the first and second signals,respectively; the microprocessor configured to determine a firsttemperature difference value by subtracting the second signal from thefirst signal; the microprocessor further configured to generate a thirdsignal to induce the compressor to recirculate the refrigerant throughthe first evaporator, the second evaporator, and the condenser to coolthe first battery module when the first temperature difference value isgreater than a threshold difference value; the microprocessor furtherconfigured to generate a fourth signal to induce the first evaporatorfan to recirculate air in the first closed flow path loop within thefirst enclosed portion when the first temperature difference value isgreater than the threshold difference value; and the microprocessorfurther configured to generate a fifth signal to induce the condenserfan to urge air past the condenser to induce the condenser to dissipatethe heat energy in the refrigerant when the first temperature differencevalue is greater than the threshold difference value.
 10. The coolingsystem of claim 1, further comprising a cooling coil that receives aliquid therein to remove heat energy from the refrigerant in thecondenser.
 11. The cooling system of claim 1, wherein the first enclosedportion is an airtight enclosed portion.
 12. A method for cooling abattery system utilizing a cooling system, the cooling system having ahousing, a first evaporator, a first evaporator fan, and a condenser,the housing having a first enclosed portion and a second enclosedportion, the first enclosed portion configured to receive a firstbattery module therein, the method comprising: recirculating air in afirst closed flow path loop within the first enclosed portion utilizingthe first evaporator fan, the first evaporator configured to extractheat energy from the air in the first closed flow path loop to reduce atemperature level of the first battery module in the first enclosedportion of the housing; receiving heat energy in a refrigerant from thefirst evaporator in a condenser disposed in the second enclosed portionof the housing and dissipating the heat energy utilizing the condenser;and recirculating the refrigerant through the first evaporator and thecondenser utilizing a compressor disposed in the second enclosedportion.
 13. The method of claim 12, wherein the cooling system furtherhas a condenser fan, a temperature sensor, and a microprocessor, themethod further comprising: generating a first signal indicative of atemperature level of the first battery module utilizing a temperaturesensor; generating a second signal to induce the compressor torecirculate the refrigerant through the first evaporator and thecondenser to cool the first battery module utilizing the microprocessorwhen the first signal indicates the temperature level of the firstbattery module is greater than a threshold temperature level; generatinga third signal to induce the first evaporator fan to recirculate air inthe first closed flow path loop within the first enclosed portion whenthe first signal indicates the temperature level of the first batterymodule is greater than the threshold temperature level; and generating afourth signal to induce the condenser fan to urge air past the condenserto induce the condenser to dissipate heat energy when the first signalindicates the temperature level of the first battery module is greaterthan the threshold temperature level.
 14. The method of claim 12,wherein the cooling system further comprises a second evaporator and asecond evaporator fan disposed in the first enclosed portion, the secondevaporator fluidly coupled to the condenser, the first enclosed portionconfigured to receive a second battery module therein, furthercomprising: recirculating air in a second closed flow path loop withinthe first enclosed portion utilizing the second evaporator fan, thesecond evaporator configured to extract heat energy from the air in thesecond closed flow path loop to reduce a temperature level of the secondbattery module in the first enclosed portion; receiving heat energy inrefrigerant from the first and second evaporators in the condenserdisposed in the second enclosed portion and dissipating the heat energyin the refrigerant utilizing the condenser; and recirculating therefrigerant through the first evaporator, the second evaporator, and thecondenser utilizing the compressor disposed in the second enclosedportion.
 15. The method of claim 12, wherein the first enclosed portionis an airtight enclosed portion.